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Indian Mountain Granodiorite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Bonsall, San Luis Rey Quadrangle, California
Object number: ROC21676
DescriptionPorphyritic igneous rock that is very light-brown on a fresh surface and grey-bown on a weathered surface. Consists of a groundmass of 60% white to tan feldspars (≤1 mm), 35% white sugary quartz (≤1 mm), and phenocrysts of 5% black euheral biotite (majority 5 mm).
In Collection(s)